1. Field of the Invention
The present invention relates to a process for production of .alpha.-hydroxycarboxylic acid amide. More particularly, it relates to a process for producing .alpha.-hydroxycarboxylic acid amide by a hydration reaction of cyanhydrin in a liquid phase.
.alpha.-Hydroxycarboxylic acid amide is used as a starting material for production of .alpha., .beta.-unsaturated carboxylic acid ester through .alpha.-hydroxycarboxylic acid amide. In particular, in case of .alpha.-hydroxyisobutyric acid amide, methyl methacrylate is obtained through methyl .alpha.-hydroxyisobutyrate. This methyl methacrylate is very important for production of polymethyl methacrylate having excellent properties.
2. Description of Related Arts
Manganese dioxide as a catalyst for hydration of cyanhydrin into the corresponding .alpha.-hydroxycarboxylic acid amide is disclosed in West German Patent No. 2131813. .delta.-Type manganese dioxide as a catalyst for hydration of acetone cyanhydrin is described in U.S. Pat. No. 4,018,829.
In Japanese Patent Application Laid-Open Nos. 57534/1988 and 57535/1988, a process for preparation of a manganese dioxide catalyst in which zinc is introduced, and a process for preparation of a manganese dioxide catalyst by reducing potassium permanganate with hydrochloric acid are disclosed.
When, however, manganese dioxide prepared by the above processes is used as a catalyst as it is, problems arise in that catalytic activity is not sufficiently high, a large amount of the catalyst must be used, the yield of the desired amide is low, and the catalytic activity abruptly drops in a short time. Thus the processes have not been put into practical use.
It has been found that in production of .alpha.-hydroxycarboxylic acid amide from cyanhydrin, the activity of a manganese dioxide catalyst has a close relationship with zirconium, vanadium, or tin, and also with an alkali metal which exists in the catalyst. Based on the findings, the present invention has been accomplished.